Loud speaker cabinet



21, 1956 E. D. BOSLEY LOUD SPEAKER CABINET Filed Oct. 5, 1955 INVENTOR. Z77ZO7Q 05257.

United States Patent LOUD SPEAKER CABINET Elmore D. Bosley, Glendale, Calif.

Application October 3, 1955, Serial N 0. 537,927

Claims. (Cl. 181-31) This invention relates to loud. speaker cabinets and more particularly to an improved mode of construction and mounting of the speaker elements within the cabinet and improved amplifying characteristics deriving from the cabinet itself.

In the reproduction of high fidelity music (commonly called hi-fi") the proper adjustment of the speaker or speakers which reproduce the lower ranges of the music has been a problem not heretofore satisfactorily solved to the satisfaction of the more critical devotees of such music. Heretofore, the usual electrical adjustments have been employed to vary the output of the various speakers but without further means to modulate the tone or resonance of the speaker for a given volume adjustment. For the speakers which reproduce the higher and intermediate ranges of the tones, the adjustment of the output of the speakers by variable resistance devices has been generally satisfactory, but for the lower or bass notes such adjustment has never been fully satisfactory.

With this consideration in mind, the principal object of the invention is to provide a means for mounting a bass speaker in a cabinet together with means for adjusting the speaker in the cabinet to produce a desired resonance to the tones produced with resultant accommodation of the entire unit to the acoustics of the room in which the speaker assembly and cabinet are located.

Another object of the invention is to provide a speaker cabinet assembly for the reproduction of music with high fidelity in which the bass speaker or speakers are capable of adjustment relative to the walls of the cabinet with resultant variation in the resonant effect of the tones emanating from the adjusted speaker or speakers.

A further object of the invention is to provide a cabinet structure for the speaker assemblies of a high fidelity music reproduction apparatus in which the bass speaker or speakers are mounted on a movable support located within the cabinet and in which such support combines with the interior wall of the cabinet to form a horn having a throat portion of variable dimension with consequent variation of the resonance of the tones produced by such bass speakers for any given volume adjustment of the input to the bass speaker or speakers.

With the foregoing objects in view, together with such additional objects and advantages as may subsequently appear, the invention resides in the parts and in the construction, combination and arrangement of parts disclosed, by way of exammple in the following specification of a presently preferred mode of execution of the invention; reference being had to the accompanying drawings which form a part of said specification and in which drawings:

Fig. l is a top perspective view of a speaker cabinet in which the present invention is incorporated,

Fig. 2 is a front elevational view of the cabinet with. certain portions broken away to disclose details of interior construction,

Fig. 3 is an enlarged scale top plan sectional view taken on the line 3-3 of Fig. 2, and

Figs. 4 and 5 are further enlarged, fragmentary sectional views taken on the line 4-4 of Fig. 3 and showing, respectively the details of construction of the top and bottom ends of the pivotal mounting for the bass speaker component of the speaker assembly.

In the illustrated embodiment of the invention, the speaker cabinet 1 comprises a semi-cylindrical back portion. 2 generated about a vertical axis, a top 3 and a bottom 4 forming a chamber. The front of the cabinet is covered by a removable cover comprising a rectangular frame 5 fitting within the opening formed by the sidewalls formed by the back 2 the under face of the top 3 and the bottom 4; said frame being covered by an ornamental, open mesh fabric. Preferably, the back member is formed from plywood which is bent and curved in the desired form.

Within the upper portion of the cabinet is a shelf 6 on which the speaker 7 for the higher ranges of notes and the speaker 8 for the intermediate ranges are mounted. These speakers form no part of the present invention and are mentioned in the interest of complete understanding of the invention.

The portion of the cabinet beneath the shelf 6 is rectangular in front elevation and is of slightly greater than semicircular configuration in plan view. The mounting for the bass speaker comprises a section of plywood 9 which along one edge is mounted in a rabbeted groove in a vertical post 10; said post being disposed adjacent to one side edge of the cabinet and hingedly mounted on a hinge pin 11 carried by a bracket 12 attached to: the inner face of the back member 2 adjacent the shelf 6 and at its lower end on a hinge pin 13 carried by a base member 14 attached to the upper face of the bottom member 4. The plywood member 9 extends from the under side of the shelf 6 to the upper face of the bottom 4 throughout its length and extends laterally from the post 10 approximately half the width of the cabinet at a diverging angle with respect to the plane of the front of the cabinet, and thence extends in a rebent portion 15 generally of the configuration of a semi-circle whose radius is somewhat less than half the radius about which the curve of the back 2 is generated and terminates in a short straight portion 16 which is tangent to the end of the curved portion 15. The bass speakers 17, 17 are mounted in the space between the end of the portion 16 and the rear face of the post 10 with the diaphragm faces thereof directed toward the inner face of the back member 2. The mounting means for the speakers may be adjusted about its pivotal connection in the chamber by any desired means; the illustrated example comprising a screw 18 extending through the back member 2 and engaging a nut element 19 carried by one end of a link 20 having its other end pivotally attached to the outer face of the curved portion 15 of the speaker mounting member 9; said screw having a pair of lock nuts 21, 21 engageable with the inner wall of the back member 2 to secure the screw against turning, once the speaker mounting member and the speakers carried thereby are adjusted to the desired position.

Referring to Fig. 3, it will be noted that the outer face of the mounting member 9 and the inner face of the back member 2 form a horn like opening extending from a throat portion 22 to the front face of the cabinet. It will be further noted that this throat can be varied in width by the adjustment of the speaker supporting member about its hinge pins. Assuming that the speaker is adjusted for a given volume of output, the adjustment of the speaker mounting to vary the width of the throat 22 will produce a decided variation in the resonance of the emitted sound. Where the speaker is located in a small room, the most desirable effect is achieved through reducing the width of the throat and for larger rooms, the

throat is increased until the desired effect is achieved. Once this adjustment is made, there is no longer need for further adjustment unless the cabinet is moved to another room having different characteristics. While the disclosed embodiment of the invention includes two bass speakers, it will be appreciated that in models of the invention for smaller rooms the overall size of the cabinet may be reduced and that only a single bass speaker may be required.

While the foregoing specification discloses a presently preferred form of the invention, the invention is not to be deemed to be limited to the exact details of construction disclosed by way of example, and it will be understood that the invention embraces all such changes and modifications in the parts and in the construction, combination and arrangement of parts as shall come within the purview of the appended claims.

I claim:

1. In a loud speaker apparatus, a back member having a sound reflecting surface of concave, substantially semi-cylindrical form, end members closing the ends of said back member to define a semi-cylindrical space, a mounting means for a loud speaker disposed in said space and adjustable toward and away from said surface of said back member; said mounting means including a member mounted for pivotal movement about an axis parallel to the axis of generation of said surface of said back member and disposed adjacent to one side edge of said back member; said pivotally mounted member extending from said point of pivotal movement across and at an acute angle to the plane of the flat face of said space for substantially half the width of said face, thence being cun'ed toward said surface in a return bend of substantially half the radius of the radius of generation of said back member surface and of slightly more than a half circle in extent and terminating in a tangentially extending free end spaced from the pivotally mounted end, a loud speaker mounted in the space between said ends of said mounting member with the sound emanating face thereof disposed toward said surface of said back member and means for adjusting said mounting means and the loud speaker as a unit about said pivotal mounting.

2. In a loud speaker apparatus, a chamber comprising a back member having a concave, semi-cylindrical sound reflecting surface and members closing the ends of said chamber, a loud speaker disposed in said chamber adjacent one side edge thereof with the sound emanating face thereof disposed toward said surface of said back member, means for supporting said loud speaker within said chamber including a wall interposed between the opposite side of said loud speaker and the open side of said chamber; said wall being curved toward said back member surface and combining therewith to a form a throat portion interposed between the loud speaker and the front of said chamber, means for pivotally mounting said wall and loud speaker carried thereby for movement about an axis parallel to the axis of generation of said surface of said back member, and means manually operable to adjustably position said supporting means on said pivotal mounting with resultant variation of said throat portion.

3. A loud speaker apparatus as claimed in claim 2 in which said adjusting means comprises screw threaded means extending through said back member and attached to said loud speaker supporting means.

4. A loudspeaker apparatus as claimed in claim 2 in which said loud speaker supporting means comprises a post, a pair of hinge pins engaging opposite ends of said post; one edge of said wall being attached to said post and extending thence at an acute angle to the front face of said chamber to about the mid width of said chamber, thence extending in a return bend toward said surface of said back member in an arc of more than a half circle and said loud speaker being disposed between said post and the end of said wall remote from said post.

5. A loud speaker apparatus as claimed in claim 4 in which an adjusting screw extends through said back member and in which the curved portion of said wall carries a link provided with a nut element engaging said screw for adjustment of said loud speaker mounting means about said hinge pins.

No references cited. 

